Adaptive energy absorption system

ABSTRACT

An energy absorbing assembly providing variable energy absorption from an energy transmitting component is mounted upon a mounting bracket for mounting the energy absorbing assembly to the energy transmitting component. An elongated strap immovably secured at a first end absorbs energy received from the energy transmitting component during a collision. Cooperating anvils are slidably received by the mounting bracket and the elongated strap is interwoven between the anvils. The anvils include generally parallel axis along which each anvil defines stepped diameters, and are slidable along the axis in response to a predetermined force to provide variable energy absorption relative to the stepped diameters.

REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims priority to U.S. ProvisionalPatent Application No. 60/379,491 filed on May 9, 2002.

TECHNICAL FIELD

[0002] This invention relates generally to an energy absorber for amotor vehicle steering column.

BACKGROUND OF THE INVENTION

[0003] Various vehicle components are known to transmit energy fromcollisions to vehicle occupants. A typical component is a steeringcolumn of a steering wheel that includes a housing or mask jacket thatcollapses during a vehicle collision. The mask jacket translates thecollision energy through an energy absorber to convert the crash energyto a fraction of the kinetic energy transferred to the vehicle operator.

[0004] A common energy absorber transmits force created by a plasticdeformation of a metal element or strap disposed in the energy absorber.An example is disclosed in U.S. Pat. No. 6,322,103 where deformation ofa flat metal strap over an anvil as disclosed to absorb crash energy. Ithas been discovered that a benefit is derived by adjusting the amount ofenergy absorbed relative to the amount of energy that may be translatedto the vehicle operator based on such variables as vehicle speed,vehicle weight, and operator weight. Also, U.S. Pat. No. 6,189,929discloses an anvil having various diameters where the anvil is adjustedto position a desired diameter in contact with the metal strap to adjustthe amount of energy absorption produced by the energy absorber.

[0005] While these devices are capable of producing various amounts ofenergy absorption, they have not provided a desirable degree of variableenergy absorption. Further, these devices are known to provide animprecise amount of energy absorption relative to the desired amount ofenergy absorption due to mechanical failures such as, for example“bounce back” where the anvil is initially moved to a desirable positionbut rebounds back to an initial position. Therefore, it would bedesirable to provide an energy absorber having both an increased degreeof variable energy absorption along with a more accurate degree ofenergy absorption.

SUMMARY OF THE INVENTION

[0006] The present invention relates to an improved energy absorbingdevice that provides variable energy absorption transmitted from anenergy transmitting component of a motor vehicle. A mounting bracketmounts the energy absorbing device to the energy transmitting component.An elongated strap is secured at at least one end for absorbing energyreceived from the energy transmitting component. Cooperating anvils areslidably received by the mounting bracket and are oriented so that theelongated strap is interwoven between the anvils. The anvils include agenerally parallel axis along which each anvil defines steppeddiameters. Each anvil is slideable along its axis in response to apredetermined force to provide variable energy absorption relative tothe stepped diameters of each anvil.

[0007] Further, a catch is included to secure each anvil in a desiredposition to prevent the anvil from moving once the desired amount ofenergy absorption is determined and the anvil has been positioned toproduce the desired amount of energy absorption.

[0008] By including cooperating anvils each slideable relative to theother, a more precise variation in the amount of energy absorption isprovided. Further, by providing a catch to secure the anvil in itsdesired position once the anvil has been moved to provide a desiredamount of energy absorption, mechanical failures known to prior artassemblies have been eliminated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Other advantages of the present invention will be readilyappreciated as the same becomes better understood by reference to thefollowing detailed description when considered in connection with theaccompanying drawings wherein:

[0010]FIG. 1 is a perspective view of a steering column having theinventive energy absorbing assembly attached thereto;

[0011]FIG. 2 is a sectional view of the energy absorbing assemblyshowing a single anvil configuration cooperable with an elongated strap;

[0012]FIG. 3 shows a perspective view of an assembly having a singleanvil;

[0013]FIGS. 3A and 3B show a sectional view of the anvil of FIG. 3 priorto firing and subsequent to firing;

[0014]FIG. 4 shows a side sectional view of a cooperable anvilembodiment having the strap interwoven therebetween;

[0015] FIGS. 5A-5D cooperable anvils having stepped diameters in variousstages of orientation.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0016] Referring to FIG. 1, an energy transmitting component in the formof a steering column is generally shown at 10. The column includes asteering shaft 12 that is disposed within a steering housing 14. Amounting brackets (16) is fixedly attached to the steering housing 14providing attachment locations 18 disposed upon opposing sides of thesteering column 10. An energy absorbing assembly 20 is secured at eachattachment location 18 to absorb energy received from the steeringcolumn 14 upon a collision of the motor vehicle.

[0017] In a collision of the motor vehicle (not shown), the vehicle bodydecelerates more rapidly than the operator so that the operator can bethrust against the steering wheel (not shown) generating an impact forcerelative to the speed of the vehicle, mass of the vehicle and mass ofthe vehicle operator amongst other variables. When the operator impactsthe steering wheel, the corresponding force on the steering columnhousing 14 causes the housing 14 to collapse relative to the vehiclebody. In order to reduce the amount of impact force transmitted to thevehicle operator, the energy absorbing assemblies 20 absorb energygenerated from the vehicle operator impacting the steering column 10.

[0018] A flat metal strap 22 includes a first end 24 fixedly attached tothe mounting bracket (16). A second end 26 is unattached, or floatsfreely relative to the assembly 20.

[0019] Referring to FIG. 2, the strap 22 is shown interwoven through theassembly 20 forming a generally S-shaped configuration between aprotuberance 28 in the assembly 20 and an anvil 30. The anvil 30 isdisplaceable as will be explained further below to alter the amount ofenergy absorption produced by the strap 22 as is shown in phantom inFIG. 2.

[0020] Referring now to FIGS. 3, 3A and 3B, the anvil 30 is shownslidably disposed within an elongated chamber 32 defined by the assembly20. An actuation device 34 is disposed at a first end 36 of theelongated chamber 32. Preferably, the actuation device 34 is anexplosive charge. However, other equivalent methods of propelling theanvil 30 through the elongated chamber 32 may be used. The actuationdevice 34 includes electrical connectors 38 that receive an electricalcharge signalled from a controller (not shown) to activate the actuationdevice 34.

[0021] A retaining pin 40 releasably secures the anvil 30 in a firstposition 42 (FIG. 3A). Upon discharging, the anvil 30 is moved from thefirst position 42 to a second anvil position 44 (FIG. 3B). A catch 46secures the anvil 30 in the second position 44 to prevent the anvil 30from rebounding back to the first position 42. An opening 48 disposed ina second chamber end 50 allows air to vent from the chamber 32 enablingthe anvil 30 to move from the first position 42 to the second position44. When the anvil 30 is located in the first position 42, a greaterlevel of energy absorption is provided than when the anvil 30 has beenmoved to the second position 44 and out of engagement with the strap 22.

[0022] Referring to FIGS. 4, and 5A through 5D, an alternate embodimentis shown having cooperating anvils 30A, 30B. Each anvil 30A, 30Bincludes stepped diameters along an anvil axis a so that each anvil 30A,30B includes at least two sections having different diameters as is bestrepresented in FIG. 5A through D as A, B, C, D. Preferably, the anvils30A, 30B include generally parallel axes a and are slidably disposed ingenerally parallel elongated chambers 32A, 32B. Referring now to FIG. 4,a sectional view shows the cooperating anvils 30A, 30B having generallyparallel axes. The strip 22 is interwoven between the cooperating anvils30A, 30B taking a generally S-shaped configuration.

[0023] Referring again to FIG. 5A, each anvil 30A, 30B is disposed infirst position 42. Therefore, a first diameter A of the first anvil 30Acooperable with a first diameter B of the second anvil 30B. As should beunderstood, if the controller determines the appropriate amount ofenergy absorption is provided from the strap 22 interacting withdiameters A and B of the anvils 30A, 30B the actuation devices 34A, 34Bare not discharged. Therefore, the energy absorption is derived from theanvils 30A, 30B as provided by diameters A and B. Referring now to FIG.5B, the second actuation device 34B is discharged by the controller toprovide a second level of energy absorption different from the firstlevel. In this case, diameter A of the first anvil 30A is cooperablewith the diameter D of the second anvil 30B. A receptor 52 comprising acompressible material such as, for example, a honeycomb material,optionally receives the first anvil 30A when propelled by the actuationdevice 34A through the elongated chamber 32A. A catch 46A secures theanvil 30A in the discharged position to prevent the anvil 30A fromrebounding once the actuation device 34A has fired.

[0024] Referring now to FIG. 5C, actuation device 34A is showndischarged moving anvil 30A to a discharged position. Now, diameter C ofanvil 30B- is cooperable with diameter D of anvil 30B providing yet anadditional level of energy absorption. As previously described, anvil30B is received by a receptor 52B and secured in the discharged positionby catch 46B.

[0025] Referring now to FIG. 5D, actuation devices 34A and 34B are showndischarged so that diameter C of anvil 30A and diameter D of anvil 30Bare cooperable. This provides still another level of energy absorption.In this case, both anvils 30A and 30B are received by the receptor 52and secured in the discharged position by catches 46A and 46B. It shouldbe understood that while two cooperating anvils 30A, 30B are shown, morethan two anvils may be used to achieve even a further level of energyabsorption. Further, providing anvils 30A, 30B with more than twostepped diameters such as, for example, three stepped diameters achievesstill further levels of energy absorption.

[0026] The invention has been described in an illustrative manner, andit is to be understood that the terminology which has been used isintended to be in the nature of words of description rather than oflimitation.

[0027] Obviously, many modifications and variations of the presentinvention are possible in light of the above teachings. It is,therefore, to be understood that within the scope of the appendedclaims, wherein reference numerals are merely for convenience and arenot to be in any way limiting, the invention may be practiced otherwisethan as specifically described.

1. An energy absorbing assembly providing variable energy absorption from an energy transmitting component, comprising: a mounting bracket for mounting said energy absorbing assembly to the energy transmitting component; an elongated strap immovably secured at a first end for absorbing energy received from the energy transmitting component; cooperating anvils slidably received by said mounting bracket, wherein said elongated strap is interwoven between said anvils; and wherein said anvils include generally parallel axis a along which each anvil defines stepped diameters A,B,C,D, and being slidable along said axis a in response to a predetermined force thereby providing variable energy absorption relative to said stepped diameters A,B,C,D.
 2. An assembly as set forth in claim 1, wherein said cooperating anvils comprise first and second anvils.
 3. An assembly as set forth in claim 2, wherein said first and second anvils each include at least two segments A,B,C,D arranged along said axis a, each segment A,B,C,D having a different diameter.
 4. An assembly as set forth in claim 3, wherein said first anvil is slidable relative to said second anvil thereby providing at least four levels of energy absorption.
 5. An assembly as set forth in claim 1, wherein said first and second anvil are each slidably disposed within a chamber elongated to receive said first and second anvil.
 6. An assembly as set forth in claim 5, including an actuation device 34 axially aligned at one end of each said anvil for providing propelling force to each of said anvils for moving said anvils from a first position to a second position.
 7. An assembly as set forth in claim 6, wherein said actuation device comprises an explosive charge.
 8. An assembly as set forth in claim 7, wherein each of said chambers includes a catch for securing said anvil in said second position.
 9. An assembly as set forth in claim 6, wherein said chamber includes an opening in an end opposite from said actuation device for providing venting to said chamber.
 10. An assembly as set forth in claim 6, wherein said chamber includes a receptor compressible to receive said first and said second anvil.
 11. An assembly as set forth in claim 10, wherein said receptor comprises a material having a honeycombed configuration.
 12. An energy absorbing assembly providing variable energy absorption from an energy transmitting component, comprising: a mounting bracket for mounting said energy absorbing assembly to the energy transmitting component; an elongated strap cooperable with said energy absorbing assembly for absorbing energy received from the energy transmitting component; and an anvil having a variable diameter and being slidable between at least first and second positions relative to said strap for introducing different diameters of said anvil into engagement with said strap thereby providing variable energy absorption relative to an interaction between said anvil and said strap, wherein said anvil is engagable with a catch thereby securing said anvil in said second position.
 13. An assembly as set forth in claim 12, wherein said catch comprises a spring clip.
 14. An assembly as set forth in claim 13, wherein said anvil includes a notch engagable with said catch 46 thereby securing said anvil in said second position.
 15. An assembly as set forth in claim 12, wherein said assembly includes a receptor comprising a material compressible to receive said anvil.
 16. An assembly as set forth in claim 15, wherein said receptor comprises a material having a honeycombed configuration.
 17. An assembly as set forth in claim 12, comprising two anvils slidable between at least first and second positions relative to said strap for introducing different diameters of said anvil into engagement with said strap.
 18. An assembly as set forth in claim 17, comprising an actuation device axially aligned at one end of said anvil for providing propelling force to said anvil thereby moving said anvil from said first position to said second position.
 19. An assembly as set forth in claim 18, wherein said actuation device comprises an explosive charge. 